Conventionally, there has been known a key switch device including, between a membrane sheet and a key top, a cup rubber that gives a reaction force according to elastic deformation to the key top, and a coil spring that depresses a contact of the membrane sheet when the key top is depressed (see Japanese Laid-open Patent Publication No. 2011-253685 and Japanese Laid-open Patent Publication No. 2009-211930).
Moreover, there has been conventionally known a key switch device including a slider that is provided integrally with a key top, and a contact depression member that is provided so as to be able to relatively move against the slider. When the key top is operated, a depression force by a weight of a contact depression member, which is independent of the operation force (i.e. a force depressing the key top), is applied to a membrane switch (see Japanese Laid-open Patent Publication No. 2011-249282).